Cleaning of water from drilling and hydraulic fracturing operations

ABSTRACT

The present disclosure pertains to systems and methods for cleaning water from drilling and hydraulic fracturing operations for reuse and/or release into the environment.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to co-pending U.S. provisional application entitled “Cleaning of Water from Drilling/Hydraulic Fracturing Operations,” having Ser. No. 61/578,367 filed on Dec. 21, 2011, which is entirely incorporated herein by reference.

BACKGROUND

Hydraulic fracturing (also known as fracking or fraccing) and drilling operations require substantial amounts of fresh water and result in flow back/produced water contaminated with particulate matter, suspended solids, bacteria, hydrocarbons, and heavy metals, among other contaminants. The purpose of cleaning the flow back/produced water from oil and gas drilling operations is to reduce the contamination potential to drinking water as well as the environment when the water or fluids are disposed of in underground wells or discharged into water systems (untreated).

In addition, the flow back/produced water must be cleaned of additives, so that the viscosity or make-up of the water does not change, and the water does not get saturated with the drilling fluids/chemicals used in the fracking and drilling processes. If the water becomes saturated or has a high concentration of the fluids/chemicals, then the water will be harmful to humans that are exposed to the water. Moreover, the entire process of drilling or fracking must be changed because the levels are elevated and will change how the process of drilling or fracking works. Thus, if the contaminated water resulting from fracking and drilling operations is not cleaned, it not only poses a threat to the environment and human life, but it cannot be used for any other purpose, including re-use in drilling and fracking operations.

SUMMARY

Embodiments of the present disclosure, in one aspect, relate to methods of and systems for cleaning water and fluids that result from drilling operations and/or hydraulic fracturing processes.

Briefly described, embodiments of the present disclosure include a system for cleaning water used in drilling or hydraulic fracturing operations comprising a site pad, where the site pad is comprised of equipment selected from a drill rig, fracking equipment, a work over rig, and a combination thereof, a mobile storage tank, where the mobile storage tank is used to store water selected from fresh water, contaminated water, and a combination thereof, where the mobile storage tank is connected to the site pad by at least one supply line and at least one return line, a cleaning unit, where the cleaning unit is connected to the mobile storage tank by at least one supply line and at least one return line, at least one mobile frac tank, where the at least one mobile frac tank is connected to the cleaning unit by at least one supply line and at least one return line, and where the at least one mobile frac tank is connected to the site pad by at least one supply line and at least one return line; and an earth pit, where the earth pit is connected to the cleaning unit by at least one supply line and at least one return line, and where the earth pit is connected to the site pad by at least one supply line and at least one return line.

Embodiments of the present disclosure include a system for cleaning water used in drilling or hydraulic fracturing operations comprising a site pad, at least one supply line, at least one waste water holding tank, at least one return line, at least one cleaning unit, and at least one clean water storage tank.

Embodiments of the present disclosure include a method for on-site cleaning of water used in drilling and hydraulic fracturing processes comprising transporting water and fluids resulting from drilling and hydraulic fracturing processes from a site pad to at least one waste water holding tank, transporting at least a portion of the water and fluids from the at least one waste water holding tank to at least one cleaning unit, where the water and fluids are cleaned, and transporting the clean water to at least one clean water storage tank.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 illustrates an embodiment of the system and method for cleaning water from drilling and hydraulic fracturing operations for reuse and/or release into the environment.

DETAILED DESCRIPTION

Before the present disclosure is described in greater detail, it is to be understood that this disclosure is not limited to particular embodiments described, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present disclosure will be limited only by the appended claims.

As will be apparent to those of skill in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has discrete components and features which may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the present disclosure. Any recited method can be carried out in the order of events recited or in any other order that is logically possible.

It must be noted that, as used in the specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a support” includes a plurality of supports. In this specification and in the claims that follow, reference will be made to a number of terms that shall be defined to have the following meanings unless a contrary intention is apparent.

Definitions:

As used herein, hydraulic fracturing refers to the breaking apart of rock formations underground that are encountered with drilling an oil or gas well.

Flow back water includes water/fluids/chemicals that come out of the well when it is drilled and/or a frac has been performed on the well.

Produced water is also water and fluids/chemicals that come out or is created from the well, while it is producing oil or gas. This produced water usually comes out of the well everyday for the life of the well. The amount that comes from the well varies from well to well.

Discussion:

The present disclosure pertains to a method of and system for cleaning water (e.g., flow back and produced) and fluids that result from drilling operations and/or hydraulic fracturing processes (e.g., oil, gas, wet and dry gas operations). In an embodiment, the method is used to clean the water of some or all of the foreign materials/contaminants so that it can be reused or released back into the environment.

The process of cleaning water is used in the drilling, fraccing, or work over of an oil or gas well. During these operations, large amounts of water are needed to crack open underground rock and shale so that the fossil fuels can be extracted from the earth. This works by pumping large volumes of water into the ground under high pressures to crack open the underground rock and/or shale layers. Fluids, sand and/or small pellets are mixed with the water and pumped down the well. This mixture varies between drilling companies and areas where the work is being performed, but the intention is to crack open the ground inside the well with the water and mixture combined, so that the fluid will work into the cracks made by the high pressures and large volumes of water, and hold open the cracks so that the fossil fuels can be extracted over time.

The volume of water used in these processes varies, depending on how deep the well is and the layers of material that need to be opened. For example, the volume of water can be from about 500 barrels and up, depending on the well and if there are multiple wells to be worked in the area. Once the water is pumped down the well under these high pressures, the well will push back up some or all of the water used in the process. The water that flows back is thus contaminated with all of the material that was used in the process, plus salt and/or brine. This water may need to be reused in the same process at the site or may need to be relocated to another neighboring well that needs this same process performed. If there is not a well within a reasonable distance, then the dirty used water may need to be disposed of.

Before re-use or disposal of the water/fluids, the used liquids must be cleaned of the drilling, fraccing or work over rig fluids. The foreign material needs to be extracted before reuse and/or disposal of the water in order to reduce the potential of contamination of ground water and drinking water supplies, as well as the environment.

According to embodiments of the present disclosure, cleaning the water is accomplished by the use of filters and/or screens to clean some or all foreign material/contaminants (e.g., drilling chemicals, rock, sand, drilling fluids, salt, i.e., anything that was not in the water prior to use of the water) from the water to archive a reusable product. The filters are comprised of all types of media, screens, and/or paper and comprise various different sizes, depending on what needs to be taken out of the water. In another embodiment, foreign material is removed by the use of chemicals, the type(s) of which is chosen depending on the weather, region, depth, soil conditions, and/or the type of well drilled, among other factors which are known to one of skill in the art. The chemical(s) removes foreign matter and/or material/contaminants that have gotten into the water or fluids used in the drilling and fracturing process.

In an embodiment of the present disclosure, the water is cleaned (e.g., it is cleaned to contain acceptable levels of contaminants, which are regulated by each state as well as the federal government) by diluting the water and/or fluids with fresh water to lower the percentage of foreign material per gallon. Other methods of cleaning the water/fluids include, but are not limited to, the use of electricity (e.g., AC/DC or both), microbes, bacteria, chemical treatment and/or natural cleaners (e.g., plant based or tree/shrub material). Electricity, for example, is used to separate the foreign material so that the water can be extracted for reuse, and all the waste can be discarded. Microbes (manmade) are organisms that can eat all of the foreign material from the water before reuse or disposal. Bacteria (natural) are used in the same process as this, but are naturally made and put into the water or increased in the water to aid in cleaning.

Drilling and hydraulic fracturing operations use water in the process of drilling a well or fracturing an existing well, so that the well is able to keep producing or to produce. These processes require water storage at the site. In an embodiment of the present disclosure, water is stored in ponds or manmade ponds/earth pits (e.g., holes dug in the ground and lined with a rubber or plastic membrane to prevent leaks). In another embodiment, water is stored in metal trailers, plastic, fiber glass and/or metal containers. In another embodiment, water is put into manmade metal tanks that comprise prefabricated metal panels that either pin together or bolt together or both. These panels are different sizes, shapes, thickness and length, depending on how much fluid needs to be stored. In an embodiment of the present disclosure, the storage containers are portable and/or mobile.

Once cleaned, the water is removed along with all mobile holding tanks or pre-fabricated containment tanks/ponds. In an embodiment of the present disclosure, the area where the tanks/ponds were, are leveled out, and grass put back, so that the area is returned to its previous condition (e.g., looks like it did before the water cleaning process began).

In an embodiment of the present disclosure, the water is treated multiple times to reduce the foreign material/contaminants in the water (e.g, 2 times, 3 times, 4 times, 5 times, 6 times, etc.). The number of treatments depends on how contaminated the water is to begin with and how clean it needs to be to meet any state and/or federal requirements. In an embodiment of the present disclosure, this is accomplished by setting up multiple units. For example, a unit that uses electricity varies in size with different rates of current. Varying the current affects the cleanliness, i.e., the current or volts change, depending on how dirty the water is or how clean the water needs to be for reuse or discharge into the environment. A unit that uses filters, microbes, and/or bacteria is similar. The mesh size of the filters and/or the amount of microbes and/or bacteria used varies to achieve different levels of cleanliness. In an embodiment of the present disclosure, any of these treatments are combined to achieve the level of cleanliness needed. In another embodiment, filters (or other cleaning methods) are used consecutively so that the water gets cleaned in one pass through the system of the present disclosure. In another embodiment, the water may be treated several times with the same cleaning method, for example, multiple treatments with electricity, multiple treatments with filters, multiple bacterial treatments, multiple treatments with microbes, or multiple treatments with dilution chemicals.

In an embodiment of the present disclosure, the amount of water that can be treated per hour or per day is adjusted (e.g., adjusted up or down), depending on how much clean water is needed per hour or day. This is accomplished by using larger units (i.e., cleaning systems and or storage containers) or multiple units (i.e., multiple cleaning systems and/or storage containers) at once to achieve the desired results.

In an embodiment of the present disclosure, the pre-fabricated tanks are made of steel panels that pin or bolt together. In another embodiment, the tanks are made to hold different volumes of water, depending on how much water is needed on the site. In another embodiment, a second, smaller tank can be brought to the site when the process of cleaning the water starts. This second, smaller tank is used to hold the cleaned water in preparation for transport to another site or to be moved for disposal or reuse. This clean water storage tank may also vary in size, depending on how many trucks are on site or how quickly the water needs to be moved or just removed from the site. In an embodiment, the clean water is put directly in to transport trucks, without any additional holding/storage tanks.

In an embodiment of the present disclosure, the water that flows back from the well for reuse or disposal can be stored in one of or a combination of earth pits that have been previously dug into the ground near the site, large temporary storage tanks that are erected on site or frac tanks that are hauled to the site empty and then filled once they are staged onsite to hold fresh water and flow back water. In an embodiment, any or all of these storage methods have a dual use. For example, they can hold fresh water before the start of the well and used water and fluids during and after the completion of the well. In an embodiment, these storage methods range from about 250 barrels and upwards of about 200,000 barrels of capacity or higher, if needed. In another embodiment, the fresh water and used water are piped or hauled by truck to one or more of the storage methods if the holding method or methods are not located on the site where the well is located.

In an embodiment of the present disclosure, the cleaning process is used to clean the nitrogen, propane and/or natural gas which is also used in the facing or work over of a well. The nitrogen, propane and/or natural gas or combination of any or all of these are also used in the process of fraccing a well or the work over of a well. Nitrogen, propane and/or natural gas is also a process to aid in cracking open the ground inside of a well. Foreign material is added to the nitrogen, propane and/or natural gas that helps to hold open the cracks in the ground so that the fossil fuels can be extracted. The foreign material has to be extracted after completing the well, therefore, to make either the nitrogen, propane and/or natural gas usable or prior to disposal of the material.

In an embodiment of the present disclosure, the entire system/method can be adapted for colder climates. In an embodiment, heaters are used to keep the water from freezing in extremely cold conditions. In another embodiment, insulation is added to the above ground storage containers or tanks. In another embodiment, covers are included as well as in line heaters on any piping that is in danger of freezing.

In an embodiment of the present disclosure, the entire system/method is monitored by electronic gauges that read everything from flow, temperature, level of treatment, and water quality, etc. The amount of flow will depend on the volume needed to complete the well. In an embodiment, water is cleaned prior to the well ever starting operations and is contained in one of the storage containment systems so that it is onsite and ready for use when the well is going to be worked. In another embodiment, the process of cleaning the water is done prior, during or after the well is worked.

In an embodiment of the present disclosure, the system and/or method is performed on any size scale to match the volume that needs to be treated, and it varies from well site and geographic location. One skilled in the art would appreciate that there is no limit to the number of times that the water, nitrogen, propane or natural gas can be reused, as long as it continues to meet safe and/or acceptable level for reuse.

In an embodiment of the present disclosure, the entire system/method is set up onsite for the completion of one well (e.g., meaning that everything is temporary). In another embodiment, at least a portion of the system/method is set up as a semi-permanent site, if multiple wells are in the area. In another embodiment, the entire system/method is set up as a semi-permanent site. In another embodiment, the system/method is used for treating other companies' water needs as well. Embodiments of the present disclosure are also used in areas where a draught has affected the amount of water accessible to oil companies. In an embodiment, once the well is completed, the entire operation can be relocated to a totally new geographical area.

FIG. 1 illustrates an embodiment of the system and method for cleaning water from drilling and/or hydraulic fracturing operations. The water cleaning system of the present disclosure comprises a site pad 101, on which the drill rig, fraccing equipment or work over rig sits. A mobile storage tank 102 is used to store either fresh or contaminated water (e.g., waste water holding tank). The mobile storage tank 102 is connected to the site pad by at least one supply line 106 and at least one return line 107. The return line 107 is optional, depending on the application.

A cleaning unit 103 is connected to the mobile storage tank 102 by at least one supply line 108 and at least one return line 109. The supply line 108 is optional, depending on the application. At least one mobile frac tank 105 is connected to the cleaning unit 103 by at least one supply line 110 and at least one return line 111. The supply line 110 is optional, depending on the application. The at least one mobile frac tank 105 is further connected to the site pad by at least one supply line 112 and at least one return line 113.

An earth pit 104 (e.g., waste water holding tank) is connected to the cleaning unit 103 by at least one supply line 114 and at least one return line 115. The supply line is optional, depending on the application. The earth pit 104 is connected to the site pad 101 by at least one supply line 116 and at least one return line 117. The return line is optional, depending on the application.

In an embodiment of the present disclosure, the system is comprised of several components (e.g., holding tanks or ponds, clean water storage tanks). In an embodiment, at least one component is designed to be mobile. In another embodiment, at least one component is designed to be semi-permanent. In yet another embodiment, at least one component of the system is designed to be permanent. Once the process is complete, the components are moved to the next site and/or removed all together to restore the land to its original condition.

In an embodiment of the present disclosure, the treated/cleaned water may also be used on a competitor's well that is closer to the previous job in order to lower transport costs. Since multiple wells are in these fields, the treated or clean reusable water can be traded between companies to further lower transport costs and reduce the need to obtain fresh water from ground sources.

EXAMPLES

A typical fracking and/or drilling site uses water from a couple of days or many months. This depends on the size of the well at the site as well as on the depth of the well being worked or drilled. Another factor includes how many stages are inside the well that need fracking. Further, there may be one well or multiple wells in one area that can use the same system without it needing to be moved, which would make the site stay in one place for up to years. This would depend on how many wells are in the same area as the cleaning system. The water could be moved to other wells in the area by trucks or extending pipe to the next location or locations, if needed.

It should be noted that ratios, concentrations, amounts, and other numerical data may be expressed herein in a range format. It is to be understood that such a range format is used for convenience and brevity, and thus, should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. To illustrate, a concentration range of “about 0.1% to about 5%” should be interpreted to include not only the explicitly recited concentration of about 0.1 wt % to about 5 wt %, but also include individual concentrations (e.g., 1%, 2%, 3%, and 4%) and the sub-ranges (e.g., 0.5%, 1.1%, 2.2%, 3.3%, and 4.4%) within the indicated range. The term “about” can include ±1%, ±2%, ±3%, ±4%, ±5%, ±6%, ±7%, ±8%, ±9%, or ±10%, or more of the numerical value(s) being modified. In an embodiment, the term “about” can include traditional rounding according to the numerical value. In addition, the phrase “about ‘x’ to ‘y’” includes “about ‘x’ to about ‘y’”.

It should be emphasized that the above-described embodiments of the present disclosure are merely possible examples of implementations, and are merely set forth for a clear understanding of the principles of the disclosure. Many variations and modifications may be made to the above-described embodiments. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims. 

Therefore, at least the following is claimed:
 1. A system for cleaning water used in drilling or hydraulic fracturing operations comprising: a site pad, wherein the site pad is comprised of equipment selected from the group consisting of: a drill rig, fracking equipment, a work over rig, and a combination thereof; a mobile storage tank, wherein the mobile storage tank is used to store water selected from the group consisting of: fresh water, contaminated water, and a combination thereof, wherein the mobile storage tank is connected to the site pad by at least one supply line and at least one return line; a cleaning unit, wherein the cleaning unit is connected to the mobile storage tank by at least one supply line and at least one return line; at least one mobile frac tank, wherein the at least one mobile frac tank is connected to the cleaning unit by at least one supply line and at least one return line, and wherein the at least one mobile frac tank is connected to the site pad by at least one supply line and at least one return line; and an earth pit, wherein the earth pit is connected to the cleaning unit by at least one supply line and at least one return line, and wherein the earth pit is connected to the site pad by at least one supply line and at least one return line.
 2. The system of claim 1, wherein the mobile storage tank comprises a capacity of about 500 gallons to about 300,000 barrels of water.
 3. The system of claim 1, wherein the cleaning unit comprises at least one of the group consisting of: a filter, electricity, microbes, bacteria, chemicals, medias, natural cleaners, dilution, and a combination thereof.
 4. A system for cleaning water used in drilling or hydraulic fracturing operations comprising: a site pad; at least one supply line; at least one waste water holding tank; at least one return line; at least one cleaning unit; and at least one clean water storage tank.
 5. The system of claim 4, wherein the at least one supply line is used for transporting cleaned water in the system and the at least one return line is used for transporting contaminated water in the system.
 6. The system of claim 4, wherein the cleaning system is comprised of at least one of the following: a filter, a chemical, electricity, microbes, bacteria, all natural cleaners, diluted with fresh water, and a combination thereof.
 7. The system of claim 4, wherein the site pad is connected to the at least one waste water holding tank by at least one return line, the waste water holding tank is connected to the at least one cleaning unit by at least one return line, the clean water storage tank is connected to the cleaning unit by at least one supply line, and the site pad is connected to the clean water storage tank by at least one supply line.
 8. The system of claim 4, further comprising at least one earth pit, wherein the earth pit comprises a pit dug into the ground at the site, and wherein the earth pit is lined.
 9. The system of claim 4, further comprising at least one mobile frac tank, wherein the at least one mobile frac tank is used for storage of fresh or contaminated water.
 10. A method for on-site cleaning of water used in drilling and hydraulic fracturing processes comprising: transporting water and fluids resulting from drilling and hydraulic fracturing processes from a site pad to at least one waste water holding tank; transporting at least a portion of the water and fluids from the at least one waste water holding tank to at least one cleaning unit, wherein the water and fluids are cleaned; and transporting the clean water to at least one clean water storage tank.
 11. The method of claim 10, wherein the water and fluids are prescreened prior to entering the at least one waste water holding tank.
 12. The method of claim 10, wherein the at least one waste water holding tank is lined with a membrane and selected from the group consisting of: a tank, a pond, and a combination thereof.
 13. The method of claim 12, wherein the membrane is comprised of a material selected from the group consisting of: rubber, plastic, and a combination thereof.
 14. The method of claim 10, wherein the cleaning unit is comprised of at least one selected from the group consisting of: a filter, electricity, microbes, bacteria, chemicals, medias, natural cleaners, dilution, and a combination thereof.
 15. The method of claim 10, wherein the water and fluids are transported to the waste water holding tank via at least one selected from the group consisting of: a supply line, a return line, a truck, and a combination thereof.
 16. The method of claim 10, wherein the water and fluids are transported to the cleaning unit via at least one selected from the group consisting of: a supply line, a return line, a truck, and a combination thereof.
 17. The method of claim 10, wherein the cleaned water is transported to the storage tank via at least one selected from the group consisting of: a supply line, a return line, a truck, and a combination thereof.
 18. The method of claim 10, wherein at least one of the holding tank, cleaning unit, and storage tank are portable.
 19. The method of claim 10, wherein at least one of the holding tank, cleaning system, and storage tank are semi-permanent to the operations site.
 20. The method of claim 10, wherein at least one of the holding tank, cleaning system, and storage tank are permanent to the operations site. 